After North Korea's July 5 missile tests, Japan, for the first time since 1945, is asking America to beef up its military presence in Japan. Why? Because Japan's hedging and tardiness in relation to missile defense has left its cities more vulnerable than they need be. That risks encouraging Pyongyang in its dangerous nuclear and missile brinkmanship. Senior U.S. and Japanese officials met in Washington on Aug. 7-8. The Japanese apparently asked the United States to send to Japan an additional U.S. warship equipped with the sophisticated Aegis radar system and the interceptor missile SM-3 (Standard Missile 3). This is...